Friends: I've been chasing a water leak on my 1996 PS 190. I already repacked the shaft, so now I've moved on to the exhaust. Yesterday I loosened everything (mufflers, pipes, flanges) and I don't see any obvious failing parts or issues. So I'm thinking I'll seal the flanges and put it all back together.

I want to ask you guys A - what type of sealer should I put between the flange and the transom? B - Should I apply any sealer/caulk to the flange/muffler/pipe connections? C - Anything else I should be looking for while everything is in pieces?

Thanks in advance for the quality replies. This forum is full of great info. One of the great benefits of owning an MC!

-Thanks -Adam

Cloaked

01-14-2013, 09:50 PM

Friends: I've been chasing a water leak on my 1996 PS 190. I already repacked the shaft, so now I've moved on to the exhaust. Yesterday I loosened everything (mufflers, pipes, flanges) and I don't see any obvious failing parts or issues. So I'm thinking I'll seal the flanges and put it all back together.

I want to ask you guys A - what type of sealer should I put between the flange and the transom? B - Should I apply any sealer/caulk to the flange/muffler/pipe connections? C - Anything else I should be looking for while everything is in pieces?

Thanks in advance for the quality replies. This forum is full of great info. One of the great benefits of owning an MC!

-Thanks -AdamRTV silicone for me.

Table Rocker

01-14-2013, 10:02 PM

I have a small leak at the front end of my Silent Master muffler that I need to repair this winter. It is a tiny hole where the horizontal cylinder meets the plug at the end. Since it is below water line, it leaks while sitting still more than when it is running.

I am going through the same process I wonder what the best method of getting the old silicone off?
I was thinking the 3-M might be to tough to get off if I ever had to do this over in the future or does that come off about as tough as silicone comes off?

I also got some t-bolt hose clamps for the flange connection, might be a little bit of over kill but I don't want to get to the rear end more than once because it is tight in the tristars..

I would advise against the 5200 on this application...too good an adhesive... RTV Silicone more than adequate....

TRBenj

01-15-2013, 10:05 AM

RTV silicone has no business below the water line of a boat! Sheesh.

5200 is what I'd choose... not sure why you'd want to do this job again in the future? 5200 would be a PITA to remove if you did, but thats because its good at what it does (sealing below the waterline). If absolutely necessary, it could be undone though.

3M 4200 or Boat Life Caulk are 2 other slightly less permanent options.

mikeg205

01-15-2013, 01:43 PM

RTV silicone has no business below the water line of a boat! Sheesh.

5200 is what I'd choose... not sure why you'd want to do this job again in the future? 5200 would be a PITA to remove if you did, but thats because its good at what it does (sealing below the waterline). If absolutely necessary, it could be undone though.

3M 4200 or Boat Life Caulk are 2 other slightly less permanent options.

I would have to disagree on the use of RTV below the waterline in that application. Especially the location of use and the draft these boat have. But I will agree polyurethane and poly sulfides are better sealants.

carlsonwa

01-15-2013, 01:52 PM

I had this same problem on my 99' last summer. Used some good permatex RTV gasket maker. Worked great!

Did the same on my raw water intake fitting this fall as well.

The oem sealant dries up.

Put a nice bead in a concentric circle about where the screw holes are. I added a little to each screw as I tighten them back in.

The only thing I would be using silicon for on my boat would be to seal the cupholders!:purplaugh

Permatex RTV has its place inside the engine (intake manifold gaskets, etc), but not on the hull.

Seriously, below the waterline? Thats just a bad idea. You get a leak there and your boat can sink. A marine sealant meant for underwater gear would be the proper thing to use.

mikeg205

01-15-2013, 09:19 PM

The only thing I would be using silicon for on my boat would be to seal the cupholders!:purplaugh

Permatex RTV has its place inside the engine (intake manifold gaskets, etc), but not on the hull.

Seriously, below the waterline? Thats just a bad idea. You get a leak there and your boat can sink. A marine sealant meant for underwater gear would be the proper thing to use.

Ok TRBenj...your MC-OCD just got a merit increase... :) :D

I would only use RTV on those exhaust screws and flanges - okay and maybe for the mature ladies on the pitot screws. Anything else would get a polyurethane or or poly sulfide...

Cool...this is almost like and oil discussion...:D :D :D

MIskier

01-15-2013, 10:06 PM

Ok TRBenj...your MC-OCD just got a merit increase... :) :D

I would only use RTV on those exhaust screws and flanges - okay and maybe for the mature ladies on the pitot screws. Anything else would get a polyurethane or or poly sulfide...

Cool...this is almost like and oil discussion...:D :D :D

Mike,

TR knows what he is talking about he is a mechanical engineer by training and does boat restorations as a hobby. What he has said about the sealants is correct, although I would be more in favor of the 3M 4200.

madcityskier

01-15-2013, 11:27 PM

5200 is worse, but to take off normal silicone look for a product called De-Solve-It.

mikeg205

01-16-2013, 09:09 AM

Mike,

TR knows what he is talking about he is a mechanical engineer by training and does boat restorations as a hobby. What he has said about the sealants is correct, although I would be more in favor of the 3M 4200.

I will agree 4200 is a better sealant then RTV... however, my chemical engineer friend got into some things with adhesives and sealants that went way over my head. He agreed it's all about work scope, application of product and surface prep - work at Los Alamos.

Anyway, I also have worked on hull repairs at in-laws summer home up in the great white north. RTV has held up and not leaked on us in over 30 years. Is 4200 stronger - I will agree yes. :)

What is the best way? Okay - 4200 - that enables my MCOCD :)

TRBenj

01-16-2013, 12:12 PM

Im not a MC owner (CC fanatic) and an EE by degree... though I do deal with mechanical stuff at work a fair amount. My recommendations on the sealant are based on practical experience (restored/rebuilt several boats from the hull up). Theyre consistent with the advice I have followed from people much smarter than I am. Silicone just doesnt belong below the waterline.

I use 5200 for pretty much everything now, but Boat Life Caulk works well too. Never used 4200 but Im sure its good stuff based on the other 3m products Ive tried. Ive had to remove running gear that had been installed with 5200 just months before and its not *that bad*. I cant think of any reason you'd need to remove an exhaust port... if you use the proper sealant, you shouldnt have to re-do it in your lifetime.

lakeoz tristar

01-16-2013, 08:09 PM

I use 5200 for pretty much everything now, but Boat Life Caulk works well too. Never used 4200 but Im sure its good stuff based on the other 3m products Ive tried. Ive had to remove running gear that had been installed with 5200 just months before and its not *that bad*. I cant think of any reason you'd need to remove an exhaust port... if you use the proper sealant, you shouldn't have to re-do it in your lifetime.[/QUOTE]

http://mastercraft.com/teamtalk/showthread.php?t=51600 POST # 6
is a reason to take it apart and then there's the fact that I am taking them apart right now.. I just like to think ahead and the previous owner had used Silicone and that was not the reason for taking the flanges off so it must have held together pretty good..But I do have some 3-M 4200 and silicone...Guess it will be a game time decision..

Wake190

01-16-2013, 09:02 PM

Thanks guys! I certainly did not intent to spark a debate. Sounds like 5200 is the best solution. I'm also going to give the mufflers a thorough inspection. Hope to have a dry bilge this year. Spring can't get here soon enough!

mikeg205

01-16-2013, 10:19 PM

5200 maybe a little strong what if you want to get your swag on or maybe go fresh air exhaust... just thinki' ahead

Lumbergh

01-16-2013, 10:47 PM

I used black RTV when I replaced my flanges with SS (the old style {94 and older} are NLA in poly 8 screw).

Did a bunch of reading and RTV was recommended a great deal. The idea being that 5200 is TOO permanent. The factory used some sort of clear silicone product.

Bunch of scraping with plastic putty knife and so on to get a clean surface to bolt the new flanges to the hull.